Teuthida is an order of marine animals commonly known as squids and cuttlefish. They are characterized by their elongated bodies, large eyes, and tentacles, which they use for capturing prey. Teuthida are found in oceans worldwide and play a significant role in marine ecosystems as both predators and prey. These creatures possess a unique internal structure called a pen, which provides support and helps maintain their streamlined shape for swimming. Teuthida are also known for their ability to change color and texture, aiding in communication and camouflage. Their diverse species exhibit a wide range of sizes and behaviors.